1. Field of the Invention
The present invention relates to fluidized bed apparatus for use in heat treating metal articles. More particularly it relates to a fluidized bed apparatus for use in the continuous heat treatment of elongated metal workpieces and especially of ferrous wires.
2. Background Art
Hitherto, in known fluidized beds for carrying out various thermal treatments on steel wires it has been difficult to maintain a stable bed fluidization, to keep the apparatus in a satisfactory condition for long operating periods and to run the thermal process reliably with minor production downtime owing to fluidization or mechanical troubles. These problems mostly stem from inadequate gas distribution devices, frequently from unsound combinations of structural materials (such as for example in fixing and joining metal and ceramic parts) and generally from unfavorable apparatus concepts comprising burners integrated in the fluidized bed apparatus enclosure. As a result, conventional fluidized bed plants are very often unwieldy constructions with little flexibility in exploitation, requiring much maintenance and tedious repair work. In addition, the continuous heat treatment of a plurality of identical wires in such plants frequently leads to excessive variations in product quality and to poor production economics.